One method of screening polymer binders for adhesion to metal surfaces, has been to place drops of the binder onto a metal panel and allowed them to dry overnight. The dried binder drops were then ‘picked’ off of the metal plate and rated, compared to the value assigned a control material. If the drops were as difficult or more difficult to remove from the plate than the control, the adhesion was deemed adequate. However, heat was not taken into account using this technique and actual tensile/adhesion values could not be measured. The only other way of evaluating nonwoven binders for use in a creping process has been to conduct testing at a customer site where a large amount of emulsion is needed to obtain meaningful data.
There is no known industry test for accurately testing polymer emulsion binders for adhesion to heated metal surfaces, such as surfaces used in creping processes for nonwoven webs, especially double recrepe (DRC) processes.
The release and adhesion tester, developed by the Tag and Label Manufacturer Institute (TLMI), has been used to evaluate various types of adhesion, where adhesive properties are required, such as pressure sensitive labels, diaper tabs, and the like.
Examples are Described Below:
U.S. Pat. No. 5,744,703 (1998) discloses use of a modified release and adhesion tester to measure the stringiness of room temperature vulcanizable silicone sealant compositions.
U.S. Pat. No. 6,107,222 (2000) discloses use of a release and adhesion tester to measure adhesive transfer to an applied paper when the coated sample is removed from the paper.
The use of the release and adhesion tester for evaluating adhesiveness of binders to a heated metal surface has not been reported.